Antibodies to double-stranded DNA (dsDNA) are prevalent in systemic lupus erythematosus (SLE), particularly in patients with lupus nephritis, yet the nature and regulation of antigenic cell-free DNA (cfDNA) are poorly understood. Null mutations in the secreted DNase DNASE1L3 cause human monogenic SLE with anti-dsDNA autoreactivity. We report that >50% of sporadic SLE patients with nephritis manifested reduced DNASE1L3 activity in circulation, which was associated with neutralizing autoantibodies to DNASE1L3. These patients had normal total plasma cfDNA levels but showed accumulation of cfDNA in circulating microparticles. Microparticle-associated cfDNA contained a higher fraction of longer polynucleosomal cfDNA fragments, which bound autoantibodies with higher affinity than mononucleosomal fragments. Autoantibodies to DNASE1L3-sensitive antigens on microparticles were prevalent in SLE nephritis patients and correlated with the accumulation of cfDNA in microparticles and with disease severity. DNASE1L3-sensitive antigens included DNA-associated proteins such as HMGB1. Our results reveal autoantibody-mediated impairment of DNASE1L3 activity as a common nongenetic mechanism facilitating anti-dsDNA autoreactivity in patients with severe sporadic SLE.
Autoantibody-mediated impairment of DNASE1L3 activity in sporadic systemic lupus erythematosus
Disclosures: P. Izmirly reported personal fees from GlaxoSmithKline outside the submitted work. J.P. Buyon reported personal fees from Bristol-Myers Squibb LN advisory board, personal fees from GSK panel on LN, personal fees from Amgen, and personal fees from Ventus outside the submitted work. B. Reizis reported being an advisor at Related Sciences. No other disclosures were reported.
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Johannes Hartl, Lee Serpas, Yueyang Wang, Ali Rashidfarrokhi, Oriana A. Perez, Benjamin Sally, Vanja Sisirak, Chetna Soni, Alireza Khodadadi-Jamayran, Aristotelis Tsirigos, Ivan Caiello, Claudia Bracaglia, Stefano Volpi, Gian Marco Ghiggeri, Asiya Seema Chida, Ignacio Sanz, Mimi Y. Kim, H. Michael Belmont, Gregg J. Silverman, Robert M. Clancy, Peter M. Izmirly, Jill P. Buyon, Boris Reizis; Autoantibody-mediated impairment of DNASE1L3 activity in sporadic systemic lupus erythematosus. J Exp Med 3 May 2021; 218 (5): e20201138. doi: https://doi.org/10.1084/jem.20201138
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